In Guerrero's capital of Chilpancingo, members of a teachers union set fire to the session hall in the state assembly building while also torching several cars outside.

The principal hall of the City Congress in Chilpancingo is set alight by members of CETEG (State Coordinator of Teachers of Guerrero teacher's union) during protests against the killing of 43 Ayotzinapa trainee teachersReutersA man tries to extinguish a fire in the principal hall of the City Congress in ChilpancingoReutersA protester runs out of the principal hall of the City Congress in Chilpancingo after it was set alightReutersProtesters are seen outside the Education Secretariat's Finance Office before it was set ablazeAFPChairs are stuck into the plasterboard wall at the comptroller's office of the Secretary of the Department of Education in GuerreroReutersFurniture is set alight outside the comptroller's office of the Secretary of the Department of EducationReutersA news photographer take pictures of cars set alight at a City Congress parking lot in ChilpancingoReuters

In neighbouring Michoacan state, which has also been a focal point of drug gang violence, students blocked the main entrance to the state capital's airport.

Another group of demonstrators broke windows, furniture and computers at local Institutional Revolutionary Party (PRI) offices in the capital of Morelia.

An employee carries a computer while running out of the building of President Enrique Pena Nieto's ruling Institutional Revolutionary Party in Morelia as protesters were approachingReutersMasked protesters vandalise an office at the building of President Enrique Pena Nieto's ruling Institutional Revolutionary Party in MoreliaReutersMasked protesters run out of the PRI building in Morelia after it was vandalisedReutersPassengers stand outside the airport as protesters block the entrance in MoreliaReuters

Anger has intensified in Mexico since Attorney General Jesus Murillo Karam said last week that evidence suggests 43 missing trainee teachers were murdered by gangsters, incinerated in a bonfire at a garbage dump and their ashes thrown in a river.

Authorities have yet to confirm that any human remains found during the search for the youths belong to the students, and officially they are still missing.

Iguala police fired on the students in two incidents, killing six people. Officers then allegedly turned over 43 arrested students to a local drug gang. Murillo Karam said members of the gang confessed to killing the students before burning their bodies and tossing the ashes and bone fragments into a river.

At least 74 people have been arrested, including Abarca and his wife, who were found hiding in a dilapidated home in a rough section of Mexico City.

Activists hold painted silhouettes representing the 43 missing students, on a pyramid at the archaeological site of Monte Alban in Oaxaca(Reuters)

The protests have led to mass cancellations this week in the hotels of Acapulco, the famous beach resort, ahead of a long holiday weekend.

Acapulco hotel occupancy rates are currently at 20%, well short of the 85% expected for this long weekend when Mexicans flock to the beaches.

As recently as three years ago, 180 cruise ships docked in the city. So far in 2014, just five have made port calls, according to statistics from local business people.